Silver(I), mercury(II) and palladium(II) complexes of functionalized N-heterocyclic carbenes: Synthesis, structural studies and catalytic activity

A series of NHC silver(I), mercury(II) and palladium(II) complexes, [(1,3-diethylbimy)6Ag4I3]I (2), [(1-benzyl-3-picolylbimy)Ag2Br2]n (3), [(1-benzyl-3-picolylbimy)HgI(CH2CN)]2 (4), {[(1-picolyl-3-npropylbimy)2Hg][Hg2I6]}n (5) and [(1,3-dipicolylbimy)PdCl]Cl (6), as well as one anionic complex [1,3-diethylbimidazolium]2[HgI4] (1) (bimy = benzimidazol-2-ylidene), have been prepared and characterized. Interestingly, a wind wheel-like Ag4I3 arrangement in 2 is formed, 1D polymeric chain containing 12-membered macrometallocycles and quadrangle Ag2Br2 units in 3 is generated, and the α-carbon atom of deprotonated acetonitrile ([CH2CN]−) in 4 participates in coordination with mercury(II) atom. In the crystal packings of complexes 1–6, 2D supramolecular layers or 3D supramolecular architectures are formed via intermolecular weak interactions, including π–π interactions, hydrogen bonds, C–H···π contacts, weak Hg···I bonds and I···I bonds. Additionally, the catalytic activity of the NHC palladium(II) complex 6 in Suzuki–Miyaura cross-coupling reaction was studied.